Process and apparatus for making plate glass



1931- H. K. Hi'rcHcocK PROCESS AND APPARATUS FOR MAKING PLATE GLASS Filed April 7. 1928 3 Sheets-Sheet l INVENTOR z X /W Nov. 24, 1931. H K, HlTcHcQcK 1,833,398

PROCESS AND APPARATUS FOR MAKING PLATE GLASS Filed April 7, 1928 3 Sheets-Sheet 2 INVENTOR ow m mm mm Nov. 24, 1931. H. K. HITCHCOCK PROCESS AND APPARATUS FOR MAKING PLATE GLASS Filed April 7, 1928 3 Sheets-Sheet 3 Patented Nov. 24, 1931 UNITED STATES PATENT OFFICE I HALBERT K. HITGHCOGK, OF PITTSBURGH, PENNSYLVANIA, AS SIGNOR TO PITTSBURGH PLATE GLASS COMPANY, A GORIEOIRA'IJION OF PENNSYLVANIA 3 PROCESS AND APPARATUS FOR MAKING PLATE GLASS" Application filed April 7, 1928. Serial 110,268,146.

The invention relates to a process and apparatus for making platelglass, such process and apparatus being shown and described, but

. not claimed, in my copending application, Serial Number 268,145, of even date herewith. The objects of the present invention are in the main the same as those of said copending application; namely, to provide a process and apparatus permitting the formation of glass sheets whose surfaces are of such smoothness that the amount of grinding is reduced to a minimum; to provide a process and apparatus which permit the formation and handling of sheets which are much thinner than the sheets heretofore made upon the regulation casting table; and to provide an apparatus which can be easily operated and is of simple construction. A further important object is to provide a process and means whereby the glass is reduced to uniform thickness after it is rolled on the table. One form of apparatus for carrying out the process is shown in the accompanying drawings, wherein:

Figure 1 is a plan view. Fig. 2 is a section on the line IIII of Fig.1. And Fig. 8 is an enlarged section on the line 11-11 of Fig. 1 through a portion only of the apparatus.

Referring to the drawings, 1 is an inclined casting table constructed in the usual wayeX- cept as. to the matter of. its inclination and provided with suitable cooling means including the pipes 2 by means of which water is circulated through the table. -The table is supported upon suitable standards 3, 3, etc. carriedby a concrete foundation or one of structural steel. The table is provided along its side edges with a pair of trams 4, 4 adapted to support the roll 5 and determine the thickness of the sheet of glass which is rolled on the table. The roll 5 is hollow and suitably water cooled by means of the swivels 6, 6, to which the water pipes '7, 7 are connected. After-1a volume of glass is teemed behind the other ends secured to the drums 9, 9 carried roller, it'is moved upward along the table on the shaft 10. The chains pass over a pair of sheaves 11, 11 journaled in the upper end of the standard 3 and are coiled up upon This 'motor drives the shaft 9 carrying the drums through the intermediary of the gears 13.

the drums when the motor 12 is operated.

. The molten glass isbrought to a position i adjacent the casting table on the cars or trucks the roller 5. The glass is then teemed across the table in the usual way and the roller. is moved along the table-to the. position A as heretofore referred to, thus rolling out the sheet of glass.

After the sheet of glass has been formed upon the table, it is allowed to slide off by gravity onto the runwayat the lower end of the table and into the roller leer 19 through which it is carried and annealed in the usual way. The runway is preferably constructed,

as indicated in Fig. 3, and consists of the water cooled platen 20 and the series of fluid cooled rollers 21. .In. order to prevent-the end of the glass sheet from: turning down into the space between the lower end of they table 585 and the platen 20, the pipe 22 is provided having a plurality of perforations along its upper edge and a blast of air is forced through the pipe until the end of the sheet has passed onto the platen; After passing over the platen the glass sheet passes between the pair ,of sizing rolls 23 and 24, which serve to reduce the sheet 'to. uniform thickness. The glass is still relatively plastic when it reaches these rolls, although provided with a skin upon its upperand lower sides due to contact with the casting table and the roll 5so that there is no difficulty in bringing it to uniform thickness. This is a desirable feature in the operation as it is a diflicult matter to keep the surface of the casting table in a true plane so that, unless it is subsequently sized, the sheet produced may vary considerably at different points in its length. This difficulty as to securing uniform thickness is also in creased by distortion of the roll 5 due to the fact that it becomes highly heated on one side when the mass-ofmolten glassis first teemed behind it which tends to make it bulge on the side in contact with the glass. The rolls 23 a d Elk-are provided with swivels 26, 26' attheir ends, to-which the water pipes 27, 2'7: are connected for circulating a cooling fluid through the rolls; The runway. comprising the platen 20 and the rolls 21 and also the sizing rolls- 23 and 24 are carried 'upon a' framework 28 upon the truck 29 to permit this apparatus to be moved from between the casting table andthe leer, this being a matter of convenience in case replacements or repairs are necessary. The truck is-mounted upon the tracks 30 and power means are provided for nioving'the truck in the form of. a screw 31 driven by the motor 32 and passing through a'nutcarried by the frame 28'. The. leer rolls 33 are provided at their ends with sprocket wheels and these are driven from the chains 35, 36, etc; 'These chains are inturn driven from the countershaft 37' (Fig. 1) through the'intermediary ofreduction gearing in the casings 38 and 39 and the countershafts 40 and 41, such countershafts being provided with sprocket wheels around which the'chains 35, .36 pass; j The. apron rolls 21 and the sizingi rolls 23 and 24 are also driven from the shaft. 31 through the intermediary. of the tumbler shafts 42" and'43 (Fig. 1) together with suitable reduction gearingin the. casing lhand chain andsprocket drives'similar to those described in connection with the leer. rolls. c f

The frame 28' which carries the platen 20 and rolls 21 also carries two. pairs of rolls 45 (Fig. for supporting the r0115 when such roll is notin service, the position ofthe roll at'su'ch time beingindicated in. Fig. 3 by the dotted circle marked C. .Therolls 45 may be suitably driven by any means, such as those described in my copending application so that the roll 5 is'kept rotatingybetween operations. This is desirable as the rolls .shouldbe kept heated by means of a gas burn.- er playing upon one. side and the constant rotation prevents the roll from becoming overheated on one-side. After'a sheet of glass has been rolled onto the table land allowed to slide off by gravity, the roll 5 is moved back from the position A (Fig; 2) to position C so that the apparatus is ready. for another casting' operation. The angle of the table l'lS preferably such that the: sheet will move 'off of the table by gravity after the roll 5 has passed off of the table and assumed the position A of Fi'g'. 2, but the invention is not liniited to making the table at an angle as steep as this, in which case some assistance may be given to the sheet in order to start it on its downward movement and keep it going if necessary. It is preferable, however, to avoidv 24 isnot limited to a construction inwhich the table 1 is permanently tilted as this feature ofthe invention is just as applicable in a construction such as;t-hatz-of'imy; copending a applic ation,; wherein the table; is normally in a horizontal position and is tilted to stow v 1 the sheet-by gravity.

What I claim is:

1'. A process of'makinga glass sheet which consists in teeminga body of glass across the lower end of'a casting table, which is inclined upwardly from said. lower end, rolling such glass upwardly along the table to form a sheet thereon, permitting the sheet as thus formed andwhile'still'plastic to slide from the table, supporting the sheet as it leaves the table and carrying it'forwardly through an annealing leer.

2. A process of. making'a glass sheet, which consists in teeming a body of molten glass 5 across adflat supporting surface,.rolling the glass into a. sheet on said surface, causingthe sheet to slide in part at least by the influence of gravityfroni the table and over a runway a while it is still relatively plastic, and rolling the sheet to-substantially uniform thickness during its movement off ofthe table and'over the runway and wh-ileit has sufficient residual heat and plasticity to permit. such sizing operation. a

3. Apparatus for making a glass sheet com.- prising a casting table fixed in inclined position and havinga fiat, plain surface for receiving the glass, a roll mounted for movement along the tablefrom its lower to its upper end and adapted to roll out into a sheet a body ofmolten glassteemed across-the lower end of the table, a roller leer in alinement V with the table, and a runway leadingfrom the lower end ofthe table into the leer.

4'. Apparatus for making a glass sheet comprising a casting table fixedin inclined position and having a flat, plain surface for receiving the glass, a roll mounted for, movement along the table from its lower, to its upper end and adapted to roll out into a sheet a body of'molten glass teemed across the lower end of the table, and a laterally extending roller runway and leer, leading from the lower end. of the table. I

5. App aratusfor makinga glass sheet comprising a casting table fixed in inclined posi- 7 tion and having a flat, plain surface for receiving the glass, a roll mounted for, move mentalong the table from its lower to its upper end and adapted to roll out into a sheet a body of molten glass teemed acrossthe lower end of the table, and a laterally extending roller runway and leer. leading from the lower end of the table, a part at least of the rollers being driven by one way clutch means which permit the sheet as it moves oversuoh rollers to move them forwardly at a higher rate of speed than that at which they are driven.

6. Apparatus for m akinga glass sheet comprising a casting table fixed in inclined position and having a. flat, plain surface for receiving the glass, a roll mounted for movement along the table from its lower to its upper end and adapted to roll out into a sheet a body of molten glass teemed across the lower end of the table, and a runway extending laterally from the lower end of the table and adapted to receive and carry away the glass sheet as it slides off of the table the table being inclined at an angle such that the glass sheet will slide down it due to the action of gravity. 7

7. Apparatus for making a glass sheet comprising a casting table fixed in inclined position and having a flat, plain surface for receiving the glass, a roll mounted for movement along the table from its lower to its upper end and adapted to roll out into a sheet a body of molten glass teemed across the lower end of the table, a runway extending laterally from the lower end of the table and adapted to receive the sheet as it slides off of the table, and means for rolling the sheet to sub stantially uniform thickness as it passes over the runway. c

In testimony whereof I have hereunto subscribed my name this 13th day of March,

H. K. HITCHCOGK. 

